The present invention relates to a novel Bacillus strain, B. subtilis DSM 2704, and to mutants and recombinants thereof. The present invention further relates to a process for producing alpha amylase, using the aforementioned strain.
Alpha amylase is one of the industrially most important enzymes and is used in large amounts, for example, in the textile and food industries, for the hydrolysis of starch. The industrial production of alpha amylase is thus of substantial economic importance.
In the manufacture of alpha amylase, it is generally known that by fermentation with different types of microorganisms of the genus Bacillus, including Bacillus subtilis and its variants, alpha amylase can be obtained in commercially useful amounts. It is particularly advantageous if the fermentation medium itself already contains high concentrations of the active enzyme. There has, therefore, been no lack of effort to obtain, by applying new cultivating and processing techniques, the highest possible enzyme concentration in the fermentation medium. For example, Yoneda et al have described a process using strain of Bacillus subtilis which is employed in industry and has been modified by means of a specific transfer of gene fragments to increase the yield of alpha amylase in the fermentation liquor from 130-150 amylase units/ml to 25,000 amylase units/ml, the term "amylase units" having an art-recognized meaning set out in detail below. See APPLIED AND ENVIRONMENTAL MICROBIOLOGY (Vol. 39) 274 et seq. (1980); MOLECULAR CLONING AND GENE REGULATION IN BACILLI (Ganesan et al. eds. 1982). This increase represents an improvement by a factor of about 170 in the production of alpha amylase. Such an increase in productivity is, however, still insufficient for the industrial production of alpha amylase.